p210 BCR/ABL exerts different effects on NER depending on cell origin. DNA repair synthesis activity on UVC-damaged plasmid was measured with the extracts from (A) BaF3, BaF3-p190, and BaF3-p210 lymphoid cells and (B) 32D, 32D-p190, and 32D-p210, BMC and BMC-p210, UT7 and UT7-p210, and HL60 and K562-p210 myeloid cells. Cell extracts were incubated with the damaged (pBS-UV) and undamaged (pHM) plasmids in a repair synthesis reaction. Ethidium bromide-stained gel and autoradiography of the dried gel (upper panels), quantification of the DNA repair activity expressed as the ratio of radiolabel incorporation in the damaged versus undamaged plasmid (middle panels, DNA repair activity in the untreated parental cell extracts was arbitrary set at 1), and the ABL proteins expression (lower panels) are shown. Results represent mean ± SD of 3 separate experiments performed with 3 independent preparations of cell extracts. The * indicates difference between values for control and BCR/ABL-expressing cells at P < .01, as determined by Student t test.